Sample Analyzer and Its Components

ABSTRACT

A sample analyzer includes a liquid aspirator to be stuck into the closed container for aspirating a sample from a closed container; a preparing section for preparing an analysis sample using the aspirated sample; and an analyzing section for analyzing the prepared analysis sample; the liquid aspirator including an elongated pipe, the pipe having a liquid flow path extending therein and a plurality of communicating sections provided in an outer surface thereof, at least one of the communicating sections communicating between an inside and an outside of the container when the pipe is stuck into the container.

CROSS-REFERENCES TO RELATED APPLICATIONS

This is a divisional application of Ser. No. 10/713,302, filed on Nov.17, 2003 which is related to Japanese Patent Application Nos.2002-334243 (filed on Nov. 18, 2002), 2002-334251 (filed on Nov. 18,2002), 2002-334272 (filed on Nov. 18, 2002), 2002-334286 (filed on Nov.18, 2002), 2002-334293 (filed on Nov. 18, 2002), and 2003-193715 (filedon Jul. 8, 2003) whose priorities are claimed under 35 USC § 119, thedisclosures of which are incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a sample analyzer for analyzing a bloodsample, a urine sample and the like and its components used therein and,particularly, to a versatile and portable sample analyzer.

2. Description of Related Art

Art hitherto known in relation to this invention is as follows.

A small-scale automatic analyzer comprising a reaction vessel diskhaving a reaction table with its circumferential portion equidistantlydivided into a plurality of portions, a plurality of reaction vesselsheld by the reaction vessel disk, means for transporting the respectivereaction vessels to a sample dispenser, to an agent dispensing positionand to an optically measuring position, means for sucking and dispensinga required amount of a sample into the reaction vessel, and means foroptically analyzing the sample in the reaction vessel (see, for example,Japanese Unexamined Patent Publication No. 11-94842 (1999));

A pipette comprising a hollow pipe having an end sealed with a sealmember, and a suction port provided in a side wall of the pipe adjacentin the vicinity of the end (see, for example, U.S. Pat. No. 5,969,272);and

A pipette comprising a thin suction pipe for sucking a liquid sample,and a thin vent pipe for ventilation during the suction, the suctionpipe and the vent pipe being disposed in parallel (see, for example,U.S. Pat. No. 5,969,272).

There have been proposed various types of blood analyzers for analyzingsamples, for example, blood. Most of the recent blood analyzers have agreater size and a higher operation speed to handle a multiplicity ofsamples in a short time. In addition, the operation of the bloodanalyzers is complicated, so that special operators should be employedas regular staff. Local hospitals and private clinics which do notfrequently need blood analyses currently commission a special bloodanalysis center to perform the blood analyses. However, it is impossibleto immediately obtain the results of blood analyses in an emergencycase. Therefore, there is a demand for a highly accurate,easy-to-operate and small-scale automatic blood analyzer.

Such a demand is applied to not only the blood analyzer but also a urineanalyzer and the like.

In such a sample analyzer, it is preferred to employ a so-called ADsystem (Autodilution system) in which the liquid sample is sucked andquantified by a suction device such as a syringe pump having a pipetteso that the analyzer may have a smaller scale with its more simplifiedconstruction. However, in the case of this system, when the pipette isinserted in a vacuum blood sampling tube (a rubber-capped tube) employedas a sample container, a negative pressure is liable to remain in thevacuum blood sampling tube. Accordingly, the sucking operation of thesuction device is not smoothly performed, resulting in erroneousquantification. Thus, there is a problem that the analysis of the samplecannot be performed accurately.

On the other hand, if a conventional vent pipe is attached to thepipette in parallel, the analyzer needs to further provide a cleaningflow system for cleaning the vent pipe, so that the construction of theanalyzer is complicated.

SUMMARY OF THE INVENTION

In view of the foregoing, it is an object of the present invention tosimplify the operation of a sample analyzer for easy handling of theanalyzer by doctors and nurses, reduce the size and weight of theanalyzer for easy transportation of the analyzer to diagnostic andmedical treatment sites, suppress the noises of the analyzer for a quietenvironment, and ensure safe and easy maintenance and inspection of theanalyzer, and particularly obtain the highly accurate results of sampleanalyses even with the use of the analyzer having a simple construction.

The present invention provides a sample analyzer comprising: a liquidaspirator to be stuck into the closed container for aspirating a samplefrom a closed container; a preparing section for preparing an analysissample using the aspirated sample; and an analyzing section foranalyzing the prepared analysis sample; the liquid aspirator includingan elongated pipe, the pipe having a liquid flow path extending thereinand a plurality of communicating sections provided in an outer surfacethereof, at least one of the communicating sections communicatingbetween an inside and an outside of the container when the pipe is stuckinto the container.

In accordance with one aspect of this invention, there is provided aliquid aspirator for aspirating liquid from a closed container,comprising: an elongated pipe having a liquid flow path extendingtherein and a plurality of communicating sections; wherein thecommunicating sections are provided in an outer surface of the pipe forcommunicating between an inside and an outside of the container when thepipe is stuck into the container.

In accordance with another aspect of this invention, there is provided aliquid aspirator for aspirating a liquid from a closed container,comprising: an elongated pipe having a liquid flow path extendingtherein and a head section tapered toward a tip thereof; wherein the tipis positioned on an axis of the pipe.

In accordance with further another aspect of this invention, there isprovided a sample analyzer comprising; a preparing section for preparingan analysis sample using a sample; an analyzing section for analyzingthe prepared analysis sample; first and second flow paths fortransporting liquid to the preparing section; first and second valvesfor opening and closing the first and second flow paths, respectively;first and second air bubble sensors for sensing an air bubble in thefirst and second flow paths, respectively, each air bubble sensoroutputting a signal; and a controller for controlling the first andsecond valves so that the valves are selectively opened, wherein thecontroller judges whether the air bubble is present in the flow pathopened by the valve based on the signals outputted from the first andsecond air bubble sensors.

In accordance with still another aspect of this invention, there isprovided an air bubble detector comprising: first and second air bubblesensors for sensing an air bubble in first and second flow paths,respectively, each air bubble sensor outputting a logical pulse signalsrepresenting a sensing time periods of the air bubbles in pulse width;and an integrating section for integrating pulse widths of the logicalpulse signals outputted from each sensor during a time period.

In accordance with still another aspect of this invention, there isprovided a sample analyzer comprising: an adaptor for holding a samplecontainer containing a sample; a rack for removably receiving theadaptor; a preparing section for preparing an analysis sample from thesample; and an analyzing section for analyzing the prepared analysissample; wherein the adaptor comprises a sample container supportingsection for receiving the sample container and a receiving tray forreceiving the sample to be spilled from the sample container,

In accordance with further another aspect of this invention, there isprovided an adaptor which is removably inserted in a rack of a sampleanalyzer to hold a sample container containing a sample, comprising: asample container supporting section for receiving the sample container;and a receiving tray for receiving the sample to be spilled from thesample container.

In accordance with still another aspect of this invention, there isprovided a sample analyzer comprising: a preparing section for preparingan analysis sample to be analyzed; and an analyzing section foranalyzing the prepared analysis sample, wherein the preparing sectioncomprises a syringe pump unit used for preparing the analysis sample,the syringe pump unit including: a first syringe pump having a firstcylinder and a first piston to be inserted in the first cylinder; asecond syringe pump having a second cylinder and a second piston to beinserted in the second cylinder; a connecting section provided betweenthe first syringe pump and the second syringe pump for connecting thefirst piston and the second piston; and a driving source for driving thefirst and second pistons through the connecting section.

In accordance with further another aspect of this invention, there isprovided a syringe pump unit comprising: a first syringe pump includinga first cylinder and a first piston to be inserted in the firstcylinder; a second syringe pump including a second cylinder and a secondpiston to be inserted in the second cylinder; a connecting section forconnecting the first piston and the second piston; and a driving sourcefor driving the first and second pistons through the connecting section.

In accordance with still another aspect of this invention, there isprovided a sample analyzer comprising: a preparing section for preparingan analysis sample to be analyzed using a sample, a first liquid and asecond liquid; and a detector for detecting a signal from the analysissample, wherein the preparing section comprises a liquid transfer unit,the liquid transfer unit including: a pump connected to a first liquidretaining section for storing the first liquid and a second liquidretaining section for storing the second liquid; a flow path forconnecting between the pump and the second liquid retaining section; athird liquid retaining section placed in the flow path; and a liquiddischarge section connected to the third liquid retaining section; thepump transporting the second liquid from the second liquid retainingsection to the third liquid retaining section and discharging the secondliquid with the first liquid via the liquid discharge section to thedetector.

In accordance with further another aspect of this invention, there isprovided a liquid transfer unit comprising: a pump connected to a firstliquid retaining section for storing a first liquid and a second liquidretaining section for storing a second liquid; a flow path forconnecting between the pump and the second liquid retaining section; athird liquid retaining section placed in the flow path; and a liquiddischarge section connected to the third liquid retaining section; thepump transporting the second liquid from the second liquid retainingsection to the third liquid retaining section and discharging the secondliquid with the first liquid via the liquid discharge section.

These and other objects of the present application will become morereadily apparent from the detailed description given hereinafter.However, it should be understood that the detailed description andspecific examples, while indicating preferred embodiments of theinvention, are given by way of illustration only, since various changesand modifications within the spirit and scope of the invention willbecome apparent to those skilled in the art from this detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a blood analyzer according to thisinvention;

FIG. 2 is a rear perspective view of the blood analyzer according tothis invention;

FIG. 3 is a perspective view of a container housing unit attached to theblood analyzer according to this invention;

FIG. 4 is a front view of a sample setting section of the blood analyzeraccording to this invention;

FIG. 5 is a top surface view of an adaptor according to this invention;

FIG. 6 is a front view of the adaptor according to this invention;

FIG. 7 is a side view of the adaptor according to this invention;

FIG. 8 is a diagram for explaining a state where the adaptor is insertedinto a sample rack according to this invention;

FIG. 9 is a diagram for explaining the operation of the sample settingsection of the blood analyzer according to this invention;

FIG. 10 is a diagram for explaining the operation of the sample settingsection of the blood analyzer according to this invention;

FIG. 11 is a diagram for explaining the operation of the sample settingsection of the blood analyzer according to this invention;

FIG. 12 is a front view of a detecting section of the blood analyzeraccording to this invention;

FIG. 13 is a front view of a pipette horizontally driving section of theblood analyzer according to this invention;

FIG. 14 is a front view of a pipette vertically sliding section of theblood analyzer according to this invention;

FIG. 15 is a view from a B-B arrow direction in FIG. 14;

FIG. 16 is a front view of the pipette vertically sliding section of theblood analyzer according to this invention;

FIG. 17 is a front view of major portions of the pipette verticallysliding section and the pipette horizontally driving section accordingto this invention;

FIG. 18 is a left side view of major portions of the pipette verticallysliding section and the pipette horizontally driving section accordingto this invention;

FIG. 19 is a left side view of a pipette vertically driving sectionaccording to this invention;

FIG. 20 is a view from a C-C arrow direction in FIG. 19;

FIG. 21 is a diagram for explaining the operation of the pipettevertically driving section according to this invention;

FIG. 22 is a diagram for explaining the operation of the pipettevertically driving section according to this invention;

FIG. 23 is a partly cut-away front view of major portions of a detectoraccording to this invention;

FIG. 24 is a partly cut-away side view of major portions of the detectoraccording to this invention;

FIG. 25 is a top surface view of a mixing chamber according to thisinvention;

FIG. 26 is a vertical sectional view of the mixing chamber shown in FIG.25;

FIG. 27 is a vertical sectional view of a pipette according to thisinvention;

FIG. 28 is a top surface view of a cleaner body according to thisinvention;

FIG. 29 is a view from a D-D arrow direction in FIG. 28;

FIG. 30 is a view from an E-E arrow direction in FIG. 28;

FIG. 31 is a diagram for explaining the operation of the cleaner bodyaccording to this invention;

FIG. 32 is a diagram for explaining the operation of the cleaner bodyaccording to this invention;

FIG. 33 is a diagram for explaining a positional relationship betweenthe cleaner body and the pipette shown in FIG. 28;

FIG. 34 is a vertical sectional view of another exemplary pipetteaccording to this invention;

FIG. 35 is an enlarged view of a major portion of the pipette shown inFIG. 34;

FIG. 36 is an end view of the pipette shown in FIG. 35;

FIG. 37 is a view from an A-A arrow direction in FIG. 35,

FIG. 38 is a top surface view illustrating another exemplary adaptoremployed in the blood analyzer according to this invention;

FIG. 39 is a front view of the adaptor shown in FIG. 38;

FIG. 40 is a side view of the adaptor shown in FIG. 38;

FIG. 41 is a diagram for explaining a state where the adaptor shown inFIG. 38 is inserted into the sample rack according to this invention;

FIG. 42 is a fluid circuit diagram according to this invention;

FIG. 43 is an electrical circuit diagram according to this invention;

FIG. 44 is a flow chart illustrating the operation of the blood analyzeraccording to this invention;

FIG. 45 is a flow chart illustrating the operation of the blood analyzeraccording to this invention;

FIG. 46 is a flow chart illustrating the operation of the blood analyzeraccording to this invention;

FIG. 47 is a detailed diagram of major portions of the fluid circuitaccording to this invention;

FIG. 48 is a front view of a syringe pump unit according to thisinvention;

FIG. 49 is a vertical sectional view of a syringe pump according to thisinvention;

FIG. 50 is a diagram for explaining the operation of major portions ofthe syringe pump unit shown in FIG. 48;

FIG. 51 is a diagram for explaining the operation of the major portionsof the syringe pump unit shown in FIG. 48;

FIG. 52 is a diagram for explaining the operation of the major portionsof the syringe pump unit shown in FIG. 48;

FIG. 53 is a top surface view of an air bubble sensor according to thisinvention;

FIG. 54 is a view from an A-A arrow direction in FIG. 53;

FIG. 55 is a signal processing circuit diagram for processingrespectively output signals from the air bubble sensors according tothis invention;

FIG. 56 is a timing chart illustrating the signals of the circuit shownin FIG. 55;

FIG. 57 is a timing chart illustrating the signals of the circuit shownin FIG. 55;

FIG. 58 is a circuit diagram illustrating another exemplary signalprocessing circuit;

FIG. 59 is a timing chart illustrating the signals of the circuit shownin FIG. 58;

FIG. 60 is a circuit diagram illustrating another exemplary switchingcircuit;

FIG. 61 is a top surface view illustrating further another exemplaryadaptor employed in the blood analyzer according to this invention;

FIG. 62 is a front view of the adaptor shown in FIG. 61;

FIG. 63 is a view from an S-S arrow direction in FIG. 61;

FIG. 64 is a top surface view of a major portion of the adaptor shown inFIG. 61;

FIG. 65 is a view from a T-T arrow direction in FIG. 64;

FIG. 66 is a diagram for explaining a state where the adaptor shown inFIG. 61 is inserted into the sample rack;

FIG. 67 is a sectional view of a pipette according to another embodimentof this invention; and

FIG. 68 is a plan view of a major portion of the pipette shown in FIG.67.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A blood analyzer according to one embodiment of this invention willhereinafter be described as one example of a sample analyzer.

The blood analyzer according to this invention is preferably automated.The “automatic” blood analyzer herein means a blood analyzer whichpermits a user to set at least one sample vessel in the analyzer, and iscapable of automatically detecting constituents of a blood samplecontained in the sample vessel, calculating values of analysis items,and outputting the results of the calculation.

The blood analyzer is adapted to analyze a blood sample of a mammal suchas a human.

Where the blood sample is a human blood sample, exemplary analysis items(measurement/analysis items) include the number of red blood cells(RBC), the number of white blood cells (WBC), the amount of hemoglobin(HGB), the value of hematocrit (HCT), the number of platelets (PLT), amean corpuscular volume (MCV), a mean corpuscular hemoglobin (MCH), anda mean corpuscular hemoglobin concentration (MCHC).

As for measurement principles, it is preferred to employ a sheath flowelectrical resistance method for the measurement of the RBC and the PLT,an electrical resistance method for the measurement of the WBC, and acalorimetric method for the measurement of the HGB. The blood sample tobe analyzed is obtained by sampling blood from a subject into a samplevessel (blood sampling tube). The blood sample may be a whole bloodsample or a sample preliminarily diluted to a predeterminedconcentration.

Particularly, where blood is sampled from an infant, the amount of theblood sample is small, so that the blood sample is preliminarily dilutedto a predetermined concentration (e.g., 26 times).

Usable as the sample vessel in the blood analyzer are common vacuumblood sampling tubes (sealed with a rubber cap) and common open bloodsampling tubes (having an open mouth) each having an outer diameter of12 to 15 mm and a length of not greater than 85 mm, and control bloodvessels each having an outer diameter of about 15 mm and a length ofabout 20 mm.

The amount of the blood sample required for the analysis is, forexample, 10 to 15 μL in the case of the whole blood sample, and 250 to350 μL in the case of the pre-diluted blood sample.

The blood analyzer comprises a main body and a container housing unit.Preferably, the main body is housed in a housing, and the containerhousing unit is removably attached to a side wall of the housing. Themain body includes a display section provided on a front upper portionof the housing. The display section includes an LCD (liquid crystaldisplay panel) for displaying the results of the analysis. If a touchpanel for inputting analysis conditions is provided integrally with theLCD, improvement in the operability of the analyzer as well as spacesaving can be achieved.

Disposed in the housing are: a sample setting section in which the usersets the sample vessel; a detecting section in which the sample isquantitatively dispensed from the sample vessel and diluted and theblood constituents of the sample are detected; a fluid controllingsection including fluid controlling devices for controlling fluidsrequired for quantitatively dispensing and diluting the sample in thedetecting section; an electrical control board section which houseselectric components for electrically controlling the detecting section,the fluid controlling section and the display section; a power supplysection for transforming an AC voltage inputted from a commercial powersupply into a lower-level DC voltage; and a printer section for printingout the results of the analysis.

It is preferred to properly lay out these sections in consideration ofease of operation and maintenance and heat generation.

Where the sample setting section is disposed in the vicinity of a frontface of the housing and an opening/closing cover (sample setting panel)is provided on the front face of the housing, for example, the user caneasily access the sample setting section to set the sample vessel in thesample setting section by opening the cover. Further, the sample vesselthus set is advantageously protected by the cover.

Where the detecting section is provided as a unit inward of a right orleft side wall of the housing, for example, the detecting section caneasily be accessed for maintenance and inspection by removing one sideplate of the housing. The detecting section preferably include a pipettedriving device, a mixing chamber, and a detector for quantitativelydispensing the blood sample from the sample vessel by means of apipette, properly diluting the blood sample and properly analyzing theblood constituents.

The pipette to be herein employed is a pipette generally referred to as“piercer” or “needle” having a sharp tip for piercing the cap of thesample vessel.

Where the fluid controlling section is disposed inward of the other sidewall opposite to the detecting section or in back-to-back relation withrespect to the detecting section, the fluid controlling section caneasily be accessed for maintenance and inspection by removing the otherside plate of the housing.

Since electromagnetic valves and pumps provided in the fluid controllingsection may cause noises, consideration is given to the silencing ofthese components for reducing the noises (including sudden noises) ofthe entire fluid controlling section, for example, to a level notgreater than 45 dB. Particularly, a pressure device such as an externalcompressor is not employed as a driving source for a fluid circuit but,instead, a negative pressure pump is provided in the housing for easyhandling of the blood analyzer. The negative pressure pump, which servesas a negative pressure source, is frequently actuated in the bloodanalyzer, requiring special consideration for the silencing thereof.

The power supply section includes components such as transistors anddiodes which generate heat. Therefore, the power supply section isdisposed in the uppermost portion of the housing, and ventilators (ventholes) are provided in the housing for spontaneous cooling of the powersupply. This arrangement obviates the need for provision of a fan forforcible cooling, and ensures silencing and space saving. With the powersupply section disposed in the uppermost portion, the other componentsare prevented from being adversely affected by the heat generated by thepower supply section.

Where the container housing unit is disposed in the side wall of thehousing, the sample vessel can easily be replaced and the containerhousing unit can easily be connected to the analyzer body. The containerhousing unit is preferably adapted to house at least two containers forcontaining a diluent and a hemolyzing agent to be used in the analyzerbody, and a container for storing a waste liquid to be drained from theanalyzer body.

Example

With reference to the attached drawings, this invention will hereinafterbe described in detail by way of another embodiment thereof. However, itshould be understood that the invention be not limited thereto.

FIGS. 1 and 2 are a front perspective view and a rear perspective view,respectively, of a blood analyzer according to the embodiment of theinvention.

As shown, an analyzer body 1 is housed in a housing 2, and includes adisplay section 3 provided on a front upper portion of the housing 2, asample setting panel 4 provided on a lower front right portion of thehousing 2 and to be opened and closed when a sample vessel is set, and abutton 5 to be pressed for opening the sample setting panel 4.

A sample setting section 6 for receiving the sample vessel, and adetecting section 7 for quantitatively dispensing a sample from thesample vessel, diluting the sample and preparing an analysis sample areprovided inward of a right side plate of the housing 2.

A fluid controlling section 8 which collectively accommodates fluiddevices such as valves and pumps for controlling fluids for thequantitatively dispensing and dilution of the sample in the detectingsection 7 is provided inward of a left side plate of the housing 2. Anelectrical control board section 9 which accommodates a board mountedwith electrical control devices for electrically controlling thedetecting section 7, the fluid controlling section 8 and the displaysection 3 is provided inward of a rear side plate of the housing 2.

A power supply section 10 for transforming a commercially available ACvoltage supplied thereto into a DC voltage, and a printer section 11 forprinting out the results of the analysis are provided inward of aceiling plate of the housing 2.

The right and left side plates, the rear side plate and the ceilingplate are removably fastened by screws, so that the respective sectionsare easily accessed for maintenance.

The power supply section 10 which includes a heat generating componentis provided in the uppermost position within the housing 2, andventilators (vent holes) 12, 13 are provided as surrounding the powersupply section 10 in the housing 2 as shown in FIG. 2. Therefore, airheated by the power supply section 10 is vented through the ventilators12, 13 for spontaneous air cooling without thermally affecting the othercomponents of the analyzer. That is, the power supply section 10 doesnot require forcible air cooling means such as a cooling fan, so thatthe size reduction and noise reduction of the analyzer can be achieved.

As shown in FIG. 3, a container housing unit 100 which accommodatescontainers 101, 103 respectively containing a diluent and a hemolyzingagent and a container 102 for storing waste liquid in combination isattached to a left side face of the analyzer body 1.

Construction and Operation of Sample Setting Section

FIG. 4 is a front view illustrating the construction of the samplesetting section 6. As shown, the sample setting panel 4 is supportedpivotally about a support shaft 14 in an arrow direction S, and biasedin the arrow direction S by a spring not shown. Above the sample settingpanel 4, the button 5 is supported pivotally about a support shaft 15and biased in an arrow direction T by a spring 16.

A claw 17 provided on an upper edge of the sample setting panel 4 isengaged with a lower edge of the button 5 to prevent the sample settingpanel 4 from opening in the arrow direction S. The sample setting panel4 is provided with a cylindrical sample rack 18 for housing the samplevessel.

As shown in FIG. 4, an adaptor detecting sensor (photo-interrupter) J1and an adaptor recognizing sensor (photo-interrupter) J2 to be describedlater are provided in the sample setting section 6.

FIGS. 5, 6 and 7 are a top surface view, a front view and a side view,respectively, of an adaptor AD1 to be inserted preliminarily in thesample rack 18 when the sample vessel (blood sampling tube) is set inthe sample rack 18. As shown, the adaptor AD1 includes a cylindricalportion 20, which serves as a sample vessel supporting section, having acylindrical recess 19 to be engaged with a lower part of the samplevessel, and a receiving tray 22 provided around an inlet 29 of therecess 19 for receiving the sample to be spilled from the sample vessel.The receiving tray 22 is provided integrally with the cylindricalportion 20. One adaptor with the recess 19 having a depth of 45 mm andan inner diameter of 16.5 mm, and another adaptor with the recess 19having a depth of 45 mm and an inner diameter of 13.6 mm are prepared asthe adaptor AD1. Therefore, these adaptors can be employed for two typesof sample vessels having different outer diameters.

An identity piece 23 projecting upward from the receiving tray 22 isprovided in at a portion of the periphery of the receiving tray 22. Theidentity piece 23 is sensed by the adaptor detecting sensor(photo-interrupter) J1 (FIG. 4) for sensing simultaneously whether theadaptor AD1 is set in the sample rack and whether the sample settingpanel 4 is opened and closed.

An elongated projection 27 projecting downward from a lower surface ofthe receiving tray 22 is provided on an outer surface of the cylindricalportion 20. When the adaptor AD1 is inserted in the sample rack 18 asshown in FIG. 8, the projection 27 is fitted into a notch 28 (FIG. 4) ofthe sample rack 18 for positioning the adaptor AD1 with respect to thesample rack 18. Whereby, the orientation of the receiving tray 22 isdetermined. In the above Example, the projection 27 may be provided inthe sample rack 18 and the notch 28 may be provided on the outer surfaceof the cylindrical portion 20.

After a user sets the adaptor AD1 with the recess 19 corresponding tothe size of the sample vessel SP1 in the sample rack 18 as shown in FIG.8, the user inserts the sample vessel SP1 into the adaptor AD1.

FIGS. 38, 39 and 40 are a top surface view, a front view and a sideview, respectively, of an adaptor AD2 to be inserted preliminarily inthe sample rack 18 when a sample vessel containing controlled bloodconstituents for test (i.e., control blood) is set in the sample rack18. As shown, the adaptor AD2 includes a cylindrical portion 20 a, whichserves as a sample vessel supporting section, having a cylindricalrecess 19 a to be engaged with a lower part of the sample vesselemployed for the control blood, and a receiving tray 22 a providedaround an inlet 29 a of the recess 19 a for receiving the sample to bespilled from the control blood sample vessel. The receiving tray 22 a isprovided integrally with the cylindrical portion 20 a. One adaptor withthe recess 19 a having a depth of 15 mm and an inner diameter of 15.6 mmis prepared as the adaptor AD2. Therefore, this adaptor can be employedfor the control blood sample vessel.

An identity piece 23 a projecting upward from the receiving tray 22 a isprovided at an upper portion of the periphery of the receiving tray 22a. The identity piece 23 a is sensed by the adaptor detecting sensor(photo-interrupter) J1 (FIG. 4) for sensing simultaneously whether theadaptor AD2 is set in the sample rack and whether the sample settingpanel 4 is opened and closed.

An elongated projection 27 a projecting downward from a lower surface ofthe receiving tray 22 a is provided on an outer surface of thecylindrical portion 20 a. When the adaptor AD2 is inserted in the samplerack as shown in FIG. 41, the projection 27 a is fitted into the notch28 (FIG. 4) of the sample rack 18 for positioning the adaptor AD2 withrespect to the sample rack 18. Whereby, the orientation of the receivingtray 22 a is determined.

An identity piece 23 b projecting downward from the receiving tray 22 ais provided at a lower portion of the periphery of the receiving tray 22a. The identity piece 23 b is sensed by an adaptor recognizing sensor(photo-interrupt) J2 (FIG. 4) for recognizing that an adaptor insertedin the sample rack 18 is the adaptor AD2 for the control blood samplevessel SP2.

After the user sets the adaptor AD2 with the recess 19 a correspondingto the size of the control blood sample vessel SP2 in the sample rack 18as shown in FIG. 41, the user inserts the control blood sample vesselSP2 into the adaptor AD2.

FIGS. 61 and 62 are a top surface view and a front view, respectively,of an adaptor AD3 employed for an open sample vessel having a smallcapacity in order to store a small-volume sample (blood) obtained frominfants or small animals. FIG. 63 is a view from an S-S arrow directionin FIG. 61.

The adaptor AD3 is preliminarily inserted in the sample rack 18 when thesample vessel is set in the sample rack 18. The adaptor AD3 supportsresiliently the sample vessel thus set. Thus, when the small-volumesample is sucked from the vicinity of a bottom of the sample vessel bymeans of a pipette to be described later, the pipette and the samplevessel are prevented from being damaged even if a tip of the pipette isbrought into contact with the bottom of the sample vessel.

As shown, the adaptor AD3 includes a cylindrical portion 20 b, and areceiving tray 22 b provided around an upper opening of the cylindricalportion 20 b for receiving the sample to be spilled from the samplevessel. The receiving tray 22 b is provided integrally with thecylindrical portion 20 b.

As shown in FIG. 63, the cylindrical portion 20 b has a cylindricalrecess 19 b extending therein. A compression spring 42 serving as afirst resilient member is inserted into a bottom 41 of the recess 19 b,and a sample vessel inserting portion 43 with a recess 46 for the samplevessel is mounted on the spring 42 for receiving a sample vessel SP3. Abottom 45 of the sample vessel inserting portion 43 and the compressionspring 42 are connected to each other by means of a pin 44 piercingthrough the bottom 41, whereby the sample vessel inserting portion 43 issupported in the recess 19 b in a vertically slidable manner. That is,when the sample vessel inserting portion 43 is pressed downward, theinserting portion 43 can be moved downward by the pressure (i.e. whileworking against the resilience of the compression spring 42). The samplevessel supporting section is comprised of the cylindrical portion 20 b,the compression spring 42, the sample vessel inserting portion 43 andthe pin 44.

FIG. 64 is a top surface view of the sample vessel inserting section 43,and FIG. 65 is a view from a T-T arrow direction in FIG. 64. As shown, aflange 47 is provided at a periphery of an upper opening of the recess46 in the sample vessel inserting section 43. A second resilient member48 for positioning the sample vessel SP3 coaxially with the recess 46 ispressed by a ring-shaped holding board 49, and fastened by two screws40. The second resilient member 48 is composed of a ring-shaped siliconerubber board and provided with four projection pieces 48 a projectingtoward the center of the opening.

A lower end portion of the recess 46 is conical in shape. When thesample vessel SP3 is inserted into the recess 46, the sample vessel ispressed toward the center of the recess 46 by the resilience of theprojection pieces 48 a, and the recess 46 with the cone-shaped lower endportion allows the sample vessel SP3 to be guided toward the center ofthe recess. Thus, the sample vessel SP3 to be inserted into the recess46 is constantly positioned along the axis of the recess 46.

In the adaptor AD3, the sample vessel SP3 having an outer diameter of7.5 to 11 mm can be accommodated into the recess 46 having a depth of 21mm. An identity piece 23 c projecting upward from the receiving tray 22b is provided at a portion of the periphery of the receiving tray 22 b.The identity piece 23 c is sensed by the adaptor detecting sensor(photo-interrupter) J1 (FIG. 4) for sensing simultaneously whether theadaptor AD3 is set in the sample rack and whether the sample settingpanel 4 is opened and closed.

An elongated projection 27 b projecting downward from a lower surface ofthe receiving tray 22 b is provided on an outer surface of thecylindrical portion 20 b. When the adaptor AD3 is inserted in the samplerack 18 as shown in FIG. 66, the projection 27 b is fitted into thenotch 28 (FIG. 4) of the sample rack 18 for positioning the adaptor AD3with respect to the sample rack 18. Whereby, the orientation of thereceiving tray 22 b is determined.

A pipette PTb with a flat tip as shown in FIGS. 67 and 68 is suitablyemployed to suck the small-volume sample from the bottom of the samplevessel SP3 when the adaptor AD3 is used. The pipette PTb will bedescribed later.

The adaptor AD1 having an inner diameter of 16.5 mm is molded by atransparent ABS resin, the adaptor AD1 having an inner diameter of 13.6mm is molded by a red ABS resin, the adaptor AD2 is molded by a blackABS resin, and the adaptor AD3 is molded by a blue ABS resin. Thus, theadaptors AD1, AD2 and AD3 are discriminated by color, so that the usercan select the type of the adaptors AD1, AD2 and AD3 and the size of thesample vessels to be used. Also, different labels may be attached to therespective adaptors for the discrimination. In order to position theadaptors, a projection may be provided in the sample rack 18 and notches(recesses) may be provided in the respective adaptors.

In this arrangement, the button 5 is slightly pivoted in a directionopposite to the arrow direction T in FIG. 4 and the lower edge of thebutton 5 is disengaged from the claw 17, when a user presses an upperend portion of the button 5. Thus, the sample setting panel 4 is pivotedabout the support shaft 14 in the arrow direction S thereby to be openeduntil a projection piece 4 a of the sample setting panel 4 is broughtinto abutment against the support plate 21 as shown in FIG. 9. In thisstate, the user inserts the sample vessel SP1, SP2 or SP3 into thesample rack 18 with the intervention of the adaptor AD1, AD2 or AD3 asshown in FIG. 10.

When the sample setting panel 4 is thereafter closed as shown in FIG.11, the sample vessel SP1 (or SP2, SP3) is held coaxially with thesample rack 18. The button 5 has a relatively large surface area (60mm×70 mm). Therefore, the user can operate the button 5 while holdingthe sample vessel.

Construction and Operation of Detecting Section

As shown in FIG. 12, the detecting section 7 includes a pipettehorizontally driving section 200, a pipette vertically sliding section300, a pipette vertically driving section 400, a mixing chamber 70 and adetector 50.

Pipette Horizontally Driving Section

FIG. 13 is a front view of the pipette horizontally driving section 200.

As shown, a driven pulley 202 and a driving pulley 203 are rotatablyprovided on a support plate 201, and a timing belt 204 is stretchedbetween the pulleys 202 and 203. The driving pulley 203 is driven by apipette back and forth motor (stepping motor) 205 provided on the rearside of the support plate 201.

A guide rail 206 is provided horizontally on an upper portion of thesupport plate 201, and a guide shaft 207 is provided horizontally on alower portion of the support plate 201. A vertically elongatedhorizontal movement plate 208 has an upper edge fitted on the guide rail206, a lower edge engaged with a sliding member 209 slidable along theguide shaft 207, and a coupling member 210 projecting from the rear sidethereof to be coupled with the timing belt 204. The horizontal movementplate 208 has screw holes 211, 212 for fixing the pipette verticallysliding member 300.

With this arrangement, the horizontal movement plate 208 is horizontallymovable by the driving of the motor 205. A pipette front position sensor(photo-interrupter) J5 for detecting the position of the horizontalmovement plate 208 is provided on the support plate 201.

Pipette Vertically Sliding Section

FIG. 14 is a front view of the pipette vertically sliding section 300,and FIG. 15 is a view from a B-B arrow direction in FIG. 14. As shown,the pipette vertically sliding section 300 includes a guide shaft 302vertically supported by a support member 301, and a pipette holder 303slidable on the guide shaft 302 with a pipette PT vertically heldtherein.

The support member 301 includes a longitudinally elongated guide groove304. A guide rod 305 horizontally projecting from the pipette holder 303is inserted in the guide groove 304 so as to be guided by the guidegroove 304, whereby the pipette holder 303 can stably be slid verticallyon the guide shaft 302. The support member 301 has notches 306, 307through which the screws extend for fixing the support member 301 to thehorizontal movement plate 208 shown in FIG. 13.

Further, the pipette holder 303 has a guide roller 308, which is engagedwith a guide arm (to be described later) of the pipette verticallydriving section 400 to cooperate with the guide arm for moving thepipette holder 303 vertically up and down.

A cleaner (pipette cleaning device) S in which the pipette PT isinserted for cleaning the exterior and interior of the pipette PT isprovided on a lower portion of the support member 301. When the pipetteholder 303 is located at the uppermost position of the support member301 (in a position shown in FIG. 14), a sharp distal tip of the pipettePT is inserted in the cleaner S.

Liquid supply/drain nipples 309, 310 and 311 fixed to a lower portion ofthe support member 301 are connected to a proximal end of the pipette PTand ports of the cleaner S via tubes 312, 313 and 314, respectively.

A screw 315 fixed to the pipette holder 303 and a screw 316 fixed to aprojection 317 of the support member 301 are provided for fixing aspacer plate 318 as shown in FIG. 16. The spacer 318 fixed as shown inFIG. 16 fixes the pipette holder 303 in the uppermost position of thesupport member 301 for preventing the sharp tip of the pipette PT frombeing withdrawn from the cleaner S.

The pipette vertically sliding section 300 is first rested on thehorizontal movement plate 208 shown in FIG. 13 with the spacer 318 fixedthereto and, after screws 319, 320 (FIG. 17) are screwed into the screwholes 211, 212 through the notches 306, 307, the spacer 318 is removedby unscrewing the screws 315,316. Thus, the pipette vertically slidingsection 300 can safely be mounted on the pipette horizontally drivingsection 200 with no possibility that the user is injured by the tip ofthe pipette PT. Where a trouble such as clogging occurs in the pipettePT, the pipette vertically sliding section 300 is entirely replaced. Atthis time, the spacer 318 is employed to safely perform a replacingoperation.

FIGS. 17 and 18 are a front view and a left side view, respectively,illustrating a state where the pipette vertically sliding section 300 ismounted on the pipette horizontally driving section 200. As shown, anend 303 a of the pipette holder 303 of the pipette vertically slidingsection 300 has a cross shape in section so as to be inserted in a mainarm (to be described later) of the pipette vertically driving section400.

Pipette Vertically Driving Section

FIG. 19 is a left side view of the pipette vertically driving section400, and FIG. 20 is a view from a C-C arrow direction in FIG. 19.

As shown in FIG. 19, the pipette vertically driving section 400 includesan elongated main arm 401 extending horizontally, a thread shaft 402extending perpendicularly through the main arm 401 and rotatablysupported by a support plate 412, a nut 403 fixed to the main arm 401 inthreading engagement with the thread shaft 402, a slide rail 404 adisposed parallel to the thread shaft 402 on the support plate 412, asliding member 404 b provided at a left end of the main arm 401 inslidable engagement with the slide rail 404 a for vertically guiding themain arm 401, and a pipette up and down motor (stepping motor) 405 fixedto the support plate 412.

Pulleys 406 and 407 are fixed to an upper end of the thread shaft 402and an output shaft of the motor 405, respectively, and a timing belt408 is stretched between the pulleys 406 and 407. Therefore, the mainarm 401 is movable vertically up and down by the driving of the motor405. A pipette top position sensor J4 for sensing that the main arm 401reaches the uppermost position is provided on the support plate 412.

A guide arm 409 is horizontally fixed to a right end of the main arm 401(is perpendicularly fixed to a paper) in engagement with the guideroller 308 of the pipette vertically sliding section 300 (FIG. 18). Themain arm 401 has a cross-shaped recess 410 provided in a surface thereofopposed to the cross-shaped end 303 a of the pipette holder 303 (FIGS.17 and 18). As shown in FIG. 20, the end 303 a of the pipette holder 303is removably inserted in an arrow direction X into the recess 410 with aproper clearance. In this case, a force for the vertical movement of themain arm 401 is directly transmitted to the pipette holder 303.

A lock rod 411 extends vertically through a middle portion of the mainarm 401 with an upper end bent portion thereof in engagement with themain arm 401. In this embodiment, the main arm 401 is composed of analuminum alloy (A5052) and has a section of 20 mm×26 mm and a length of108 mm. The guide arm 409 is prepared by folding a 0.5-mm thick steelplate (SECC) into an open square shape in section, and has a length of180 mm.

Operations of Pipette Horizontally Driving Section, Pipette VerticallySliding Section and Pipette Vertically Driving Section

When the blood sample is quantitatively dispensed out of the samplevessel SP1 set in the sample rack 18 in the sample setting section 6,the pipette back and forth motor 205 is driven to insert the end 303 aof the pipette holder 303 into the recess 410 of the main arm 401 asshown in FIG. 20.

The pipette up and down motor 405 is driven to move up the main arm 401until the actuation of the pipette top position sensor J4 (FIGS. 4 and19). With the end 303 a is fitted in the recess 410, the centers of thethread shaft 402, the pipette PT and the sample vessel SP1 are presentin the same plane, and a moment exerted on the pipette PT by the threadshaft 402 is minimized. Therefore, the torque of the motor 405 isefficiently converted into a pipette lowering force, when the pipette PTis lowered by the motor 405.

Then, the motor 405 is driven to lower the pipette PT through athrough-hole 26 a of a sample vessel lift preventing stopper 26 as shownin FIG. 21, and to allow the pipette PT to virtually reach the bottom ofthe sample vessel SP1 as shown in FIG. 22. Where the sample vessel SP1is a vacuum blood sampling tube with a rubber cap, it is necessary topiece the rubber cap with the tip of the pipette PT. Therefore, an inputelectric current greater than usual is supplied to the motor 405 from adriver circuit section (to be described later) to provide a greateroutput torque when the pipette PT is lowered to pierce through therubber cap.

When the pipette PT is lowered, the lock rod 411 is brought intoengagement with a lock hole 25 provided in a projection piece 24projecting inward of the sample setting panel 4 as shown in FIG. 22, sothat the pipette PT and the sample vessel SP1 are prevented from beingdamaged when the sample setting panel 4 is inadvertently opened. Wherethe sample vessel SP2 is set in the sample rack 18 with the interventionof the adaptor AD2 as shown in FIG. 41, the adaptor recognizing sensorJ2 is actuated. Therefore, a control section 500 to be described latercontrols a lowering distance of the pipette PT to allow the tip of thepipette PT to virtually reach the bottom of the sample vessel SP2.

In the state shown in FIG. 22, the pipette PT is employed for samplingthe blood sample from the sample vessel SP1.

Upon completion of intake of the blood sample, the pipette PT returns tothe position shown in FIG. 21. Although there would be a possibilitythat the sample vessel SP1 along with the pipette PT is lifted togetherwith the rubber cap sticking thereto when the pipette PT is removed fromthe sample vessel SP1, the stopper 26 prevents the rubber cap from beinglifted together.

When the pipette PT is returned to the position shown in FIG. 21, thepipette back and forth motor 205 is driven to withdraw the end 303 a ofthe pipette holder 303 from the recess 410 of the main arm 401 in adirection opposite to the arrow direction X in FIG. 20, and then movethe pipette PT to an upper side of the mixing chamber 70 and thedetector 50 with the guide roller 308 rotated in contact with the innersurface of the guide arm 409. Then, the pipette up and down motor 405 isdriven, whereby a driving force thereof is transmitted to the pipetteholder 303 through the main arm 401, the guide arm 409 and the guideroller 308. Thus, the pipette PT is lowered and then lifted.

Construction of Detector

FIGS. 23 and 24 are a partly cut-away front view and a partly cut-awayside view, respectively, of major portions of the detector 50. Thedetector 50 is composed of a transparent polysulfone resin. As shown,the detector 50 includes first, second and third container chambers 51,52, 53 for containing liquids for the analysis. The first containerchamber 51 has an upper portion open to the atmosphere. The firstcontainer chamber 51 and the third container chamber 53 communicate witheach other.

A ruby orifice disk 54 is provided as a partition between the firstcontainer chamber 51 and the second container chamber 52, and the disk54 has an orifice 55 having a diameter of 80 μm. The second containerchamber 52 is provided with a jet nozzle 56. The jet nozzle 56 issupported by a nozzle support member 57 and a first electrode 58, andextends through the second container chamber 52 with its distal endfacing toward the orifice 55 and with its tail end communicating with aliquid supply nipple 59. The first electrode 58 is composed of astainless steel, and exposed to the inside of the second containerchamber 52.

The detector 50 further includes nozzles 60, 61 for supplying thediluent and the hemolyzing agent to the first container chamber 51,nipples 63, 64 for supplying and draining liquid into/from the secondcontainer chamber 52, and a liquid draining nipple 65 and an air bubbleinjecting nipple 66 provided in the bottom of the third containerchamber 53.

As shown in FIG. 24, the detector 50 further includes a second platinumelectrode 67 projecting in the first container chamber 51, and a lightemitting diode 68 and a photodiode 69 respectively disposed on oppositesides of the third container chamber 53. The light emitting diode 68emits light having a wavelength of 555 nm, and the photodiode 69 detectsthe intensity of the light transmitting through the third containerchamber 53. The light emitting diode 68 and the photodiode 69 areemployed for measurement of a hemoglobin amount (HGB).

As will be described later, the first and third container chambers 51,53 are employed for preparation of a white blood cell measurementspecimen, and the first and second container chambers 51, 52 areemployed for counting the numbers of the white blood cells, theplatelets and the red blood cells.

Construction of Mixing Chamber Container for Mixing Liquids)

FIGS. 25 and 26 are a plan view and a vertical sectional view,respectively, of the mixing chamber 70. The mixing chamber 70 includes acontainer portion 71 for mixing the blood sample. The container portion71 has a cylindrical shape with its top open to the atmosphere. Adiluent supplying nipple 72 is provided in an upper portion of thecontainer portion 71. A nipple 73 for discharging a liquid mixture, anipple 74 for draining residual liquid from the container portion 71,and a nipple 75 for injecting air bubbles (air) for agitating the liquidin the container portion 71 are provided in the bottom of the containerportion 71.

The nipples 72, 73, 74, 75 are respectively connected to a liquid supplyport 72 a, liquid discharge ports 73 a, 74 a, and an air supply port 75a, which communicate with an interior surface of the container portion71. The liquid supply port 72 a opens so as to supply the liquid fromthe upper portion along the inner circumferential surface of thecontainer portion 71. Where the diluent is supplied into the mixingchamber 70 as will be described later for cleaning the chamber, theinterior surface of the container portion 71 is efficiently cleaned withthe diluent ejected from the liquid supply port 72 a.

The mixing chamber 70 is produced by injection-molding a thermoplasticresin such as a polyether amide having a chemical resistance. Theinterior surface of the container portion 71 has been roughened to anarithmetic average surface roughness Ra of 0.29 μm so as to be impartedwith a sufficiently high wettability with respect to the diluent.Therefore, the diluent injected from the liquid supply port 72 a issupplied into the bottom of the container portion 71 without residing asliquid drops on the interior surface, so that the blood samplepreliminarily supplied can accurately be diluted predetermined times.

Constructions and Operations of Pipette and Cleaner (Pipette CleaningDevice)

FIG. 27 is a vertical sectional view of the pipette PT. The pipette PTis a stainless steel pipe, which has a suction flow path 31 coaxiallyextending therein, and a distal tip sharply cut at an angle α of 30degrees. Where the sample vessel SP1 with the cap is employed, the capis pierced with the distal tip. A distal end of the suction flow path 31is sealed with a stainless steel seal 33, and a suction port 32 is openin a side wall of the pipette PT with its axis extending perpendicularlyto the axis of the pipette PT.

FIG. 28 is a plan view of the cleaner body 80. FIGS. 29 and 30 are viewsfrom a D-D arrow direction and from an E-E arrow direction, respectivelyin FIG. 28. As shown, a cleaner body 80 has a pipette through-hole 81centrally extending therethrough, so that the pipette PT is verticallyinserted in the pipette through-hole 81 from an inlet 81 a to an outlet81 b. The pipette through-hole 81 has a round cross section.

The pipette through-hole 81 includes a pipette guide hole 82, a firstthrough-hole 83 and a second through-hole 84 serially and coaxiallydisposed in this order from the inlet 81 a to the outlet 81 b. Thepipette guide hole 82 has an inner diameter slightly greater than theouter diameter of the pipette PT, and serves to guide the pipette PT soas to align the axis of the pipette PT with the axes of the first andsecond through-holes 83, 84.

On the other hand, the first and second through-holes 83, 84 constitutea pipette cleaning hole for cleaning the pipette. A first opening 85 aand a second opening 85 b are formed in the first and second throughholes 83, 84, respectively.

The cleaner body 80 includes a cleaning liquid drain path 87 a allowingcommunication between the first opening 85 a and a cleaning liquiddraining nipple 87, and a cleaning liquid supply path 88 a allowingcommunication between the second opening 85 b and a cleaning liquidsupplying nipple 88.

The pipette guide hole 82, the first through-hole 83 and the secondthrough-hole 84 respectively have inner diameters D1, D2 and D3 whichare set at 105%, 115% and 200% of the outer diameter of the pipette PT.Where the pipette PT has an outer diameter of 2.0 mm, for example,D1=2.1 mm, D2=2.3 mm and D3=4.0 mm.

When the cleaning liquid (the diluent in this embodiment) is suppliedfrom the nipple 88 into the second through-hole 84 and sucked from thenipple 87 with the pipette PT extending from the upper side to the lowerside through the pipette through-hole 81 as shown in FIG. 31, thecleaning liquid flows in uniform contact with the exterior of thepipette PT from the second through-hole 84 into the first through-hole83, and drained from the nipple 87.

Therefore, when the pipette PT is moved up in the arrow direction Z inthis state, the blood sample and the like adhering on the exterior(outer circumferential surface) of the pipette PT is washed away withthe cleaning liquid and drained.

When the cleaning liquid flows into the nipple 87 from the nipple 88,the distal suction port 32 with the tip of the pipette PT is kept withinthe first through-hole 83 a as shown in FIG. 32. When the cleaningliquid is supplied from the proximal end of the pipette PT to the distalsuction port 32 with the tip of the pipette PT, the cleaning liquidhaving passed through the suction flow path 31 of the pipette PT isdrained from the suction port 32 of the pipette PT, and sucked into thenipple 87 through the first opening 85 a but not drained into the secondthrough-hole 84. Thus, the interior of the pipette PT (i.e., the innersurfaces of the suction flow path 31 and the suction port 32 of thepipette PT) is cleaned.

A positional relationship between the cleaner body 80 and the pipette PTas seen axially of the pipette PT is shown in FIG. 33. As shown, thepipette PT is positioned with respect to the cleaner body 80 with theaxis of the suction port 32 and the axis of the opening 85 b of thecleaning liquid drain path 87 a forming an angle θ of greater than 90degrees. This is because the following phenomena have experimentallybeen observed.

(1) If θ□90 degrees, the diluent (to be described later) filled in thesuction flow path 31 and the suction port 32 of the pipette PT is suckedout by the negative pressure in the cleaning liquid drain path 87 a anda void occurs in the suction port 32 when the exterior or interior ofthe pipette PT is cleaned. Therefore, the blood sample is introducedinto the void in the suction port 32 before the blood sample is suckedto be quantified by means of the pipette PT. Accordingly, the bloodsample is sucked into the pipette PT in an amount greater by thepreviously introduced amount than an intended amount, resulting inerroneous quantifying.

(2) If θ>90 degrees, the negative pressure in the cleaning liquid drainpath 87 a exerts no direct effect on the suction port 32. Therefore,accurate quantifying can be ensured because no void occurs in thesuction port 32 when the exterior or interior of the pipette PT iscleaned.

Another Exemplary Pipette

FIG. 34 is a side view illustrating another exemplary pipette PTa to besuitably employed instead of the pipette PT (FIG. 27) where a vacuumblood sampling tube (sealed with a rubber cap) is particularly used asthe sample vessel SP1, and FIG. 35 is an enlarged view of a majorportion of FIG. 34, FIG. 36 is an end view of the pipette PTa, and FIG.37 is a view from an A-A arrow direction in FIG. 35.

As shown, the pipette PTa is a stainless steel pipe having an outerdiameter of 1.5 mm, which has a suction flow path (fluid path) 31 ahaving an inner diameter of 0.5 mm centrally extending therein. A sharppyramidal portion (head) 37 having a trigonal pyramid shape taperedtoward an apex T is formed at a distal end of the pipette PTa as shownin FIGS. 34 and 35. The apex T is positioned on the central axis of thepipette PTa as shown in FIG. 36. With this construction, a loweringforce of the pipette PTa is concentrated at the apex T, whereby therubber cap of the sample vessel SP1 is easily pierced with the pipettePTa. The pyramidal portion 37 may have a conical shape or a quadrangularpyramid shape. The rubber cap through which the pipette PTa pierces hasa thickness of about 5 mm.

The suction flow path 31 a has a distal end portion sealed with astainless steel seal as in that of the pipette PT of FIG. 27. Thepipette PTa has a suction port 32 a (FIG. 35) open in a side wallthereof. The suction port 32 a has an axis extending perpendicularly tothe axis of the pipette PTa, and communicates with the suction flow path31 a (FIG. 35).

Further, the pipette PTa has three elongated recesses 34, 35 and 36 eachhaving a groove shape provided in an outer surface thereof as extendingin line parallel to the axis thereof as shown in FIG. 34. The pyramidalportion 37 has a length L1 of 4 mm, the recesses 34, 35 and 36 havelengths L2, L4 and L6 of 25 mm, 20 mm and 30 mm, respectively. Aninterval L3 between the recesses 34 and 35 is 5 mm, and an interval L5between the recesses 35 and 36 is 5 mm. From the viewpoint of reductionin production costs, it is preferred that the recesses 34, 35 and 36 areprovided in line parallel to the axis of the pipette PTa. However, therecesses may be provided in two or three lines parallel to the axis ofthe pipette PTa or may be provided in an outer surface of the pipettePTa as extending spirally thereof.

After the distal end of the pipette PTa is lowered to pierce through therubber cap, the recess 34 serves to let the internal pressure of thesample vessel back to the atmospheric pressure immediately. When thepipette PTa is kept lowering, a part of the rubber cap goes into therecess 34, and then is pushed out through the interval portion L3 of thepipette PTa.

When the pipette PTa is further lowered, the part of the rubber cap goesinto the recess 35 and is pushed out through the interval portion L5 ofthe pipette PTa, so that a through-hole is enlarged. When a distal tipof the pipette PTa virtually reaches the bottom of the sample vessel SP1and the recess 36 is disposed opposedly to the rubber cap, the part ofthe rubber cap does not go into the recess 36. Accordingly, the recess36 serves to define an air hole through the rubber cap, and the samplevessel SP1 has an inside open to the atmosphere via the air hole to asufficient degree. Thus, the sample (blood) is sucked smoothly from thesample vessel SP1 by means of the pipette PTa.

The three elongated recesses 34, 35 and 36 are arranged in a straightline extending along the axis of the pipe from one ridgeline of thetrigonal pyramid formed at the distal end of the pipette PTa as shown inFIG. 36. With this construction, the rubber cap is split by the pipettePTa with its ridgeline portions of the trigonal pyramid after beingpierced with the pipette PTa, and the recess 36 is disposed opposedly toone of the split portions of the rubber cap. Thus, the recess 36 candefine the air hole through the rubber cap more effectively.

The exterior of the pipette PTa is cleaned by the cleaner S as in thatof the pipette PT. At the same time, the recesses 34, 35 and 36 arecleaned in this manner. As a result, there is no need to provide anothercleaner in the analyzer for cleaning only the recesses 34, 35 and 36.

FIGS. 67 and 68 are a sectional view of a pipette PTb and a plane viewof a distal end thereof, respectively, according to another embodimentof this invention. The pipette PTb is employed suitably to suck asmall-volume sample from the vicinity of a bottom of an upper-opensample vessel having a small capacity for storing the small-volumesample.

As shown, the pipette PTb is composed of a stainless steel pipe havingan outer diameter of 1.5 mm, which has a suction flow path 31 b havingan inner diameter 0.6 mm coaxially extending therein. The pipette PTbhas a distal end with round portions having a radius of 0.4 mm and witha groove 32 b crossing diametrically over the distal end. The width ofthe groove 32 b is the same as the diameter of the suction flow path 31b, and the depth of the groove 32 b is 0.3 mm. With such a distal endshape, the distal end of the pipette PTb is brought into contact withthe bottom of the sample vessel to suck up the sample, and then thesample is sucked into the suction flow path 31 b through the groove 32b.

Constructions of Fluid Circuit and Electrical Circuit

FIG. 42 is a system diagram illustrating a fluid circuit according tothe embodiment of the invention. In the fluid circuit, the pipette PT,the cleaner S, the mix chamber 70, the detector 50, a negative pressurepump P1, a liquid draining pump P2, an air pump P3, syringe pumps SR1,SR2, SR4, a diluent chamber SC1, a hemolyzing agent chamber SC2, a wasteliquid chamber WC, the diluent container 101, the waste liquid container102, the hemolyzing agent container 103, air bubble sensors BS1, BS2,and valves SV1 to SV16, SV18 to SV20 and SV23 to SV 28 are connected byfluid supply tubes (flow paths). The syringe pumps SR1, SR4 are drivenby a syringe pump motor STM4, and the syringe pump SR2 is driven by asyringe pump motor STM5. Stepping motors may be employed as the syringepump motors STM4, STM5. The syringe pumps SR1, SR4 and the syringe pumpmotor STM4 are integrated as a syringe pump unit PU (see FIG. 48).

A preferred example of the diluent is CELLPACK available from SysmexCorporation, and a preferred example of the hemolyzing agent isSTROMATOLYSER WH available from Sysmex Corporation.

FIG. 43 is a block diagram illustrating the electrical circuit accordingto the embodiment of the invention. The power supply section 10transforms a voltage supplied from a commercial AC power supply into aDC voltage (12V), which is supplied to the control section 500 and thedriver circuit section 501. The control section 500 is comprised of amicroprocessor including a CPU, a ROM and a RAM, and the driver circuitsection 501 includes driver circuits and I/O ports.

The driver circuit section 501 performs A-D conversion on output signalsof the adaptor detecting sensor J1, the adaptor recognizing sensor J2,the pipette top position sensor J4, the pipette front position sensorJ5, a pressure sensor J6 for detecting the negative pressure in thewaste liquid chamber WC, a float switch J7 for detecting a liquid amountaccumulated in the waste liquid chamber WC, the air bubble sensors BS1and BS2, a hemoglobin detecting section 502 for allowing the lightemitting diode 68 to emit light and for receiving an output from thephotodiode 69, and a resistance-type detecting section 503 for detectinga change in impedance between the electrodes 58 and 67 through which aDC constant current passes, and outputs converted signals to the controlsection 500.

The control section 500 receives output signals from the driver circuitsection 501 and output signals from the touch panel 3 b, and processesthese signals thus received according to a predetermined processingprogram. The control section 500 causes the driver circuit section 501to drive the pipette up and down motor 405, the pipette back and forthmotor 205, the syringe pump motors STM4, STM5, the negative pressurepump P1, the liquid draining pump P2, the air pump P3 and theelectromagnetic valves SV1 to SV16, SV18 to SV20 and SV3 to SV28 on thebasis of the results of the processing. Then, the control section 500controls the liquid crystal display 3 a of the display section 3 and theprinter section 11 to display and print out analysis conditions,analysis items, analysis results and the like.

Analytic Operation to be Performed by Blood Analyzer

An analytic operation to be performed by the blood analyzer shown inFIG. 1 will hereinafter be described with reference to the fluid circuitshown in FIG. 42 and a flow chart shown in FIG. 44.

As shown in FIG. 44, when the power supply to the blood analyzer isturned on (Step S1), a diluent required for preliminary cleaning istransported from the container 101 into the diluent chamber SC1 (Step S1a). Then, when a measurement preparation period required for preparatoryoperations for the analysis including the preliminary cleaning operationis elapsed (Step S2), the diluent and hemolyzing agent required forpreparation of an analysis sample are transported from the containers101 and 103 into the diluent camber SC1 and the hemolyzing agent chamberSC2, respectively (Steps S2 a, S2 b), and a message “Ready” is displayedon the liquid crystal display 3 a of the display section 3.

Then, the user sets the sample vessel SP1 (or SP2, SP3) in the samplesetting section 6 (FIG. 4) (Step S4). Where a sample in the samplevessel thus set is a whole blood sample, the user selects a whole bloodmode by means of the touch panel 3 b of the display section 3 and, wherethe sample is a diluted sample, the user selects a pre-diluted mode(Step S5).

Then, the user presses a start button on the touch panel 3 b (Step S6).Where the sample vessel SP1 (or SP2, SP3) is not set and/or the samplesetting panel 4 is not closed in Step S4, the sensor J1 detects such asituation, so that the analyzer does not operate. Where the samplevessel SP1 (or SP2, SP3) is set and the sample setting panel 4 isclosed, the analyzer starts operating. Where the whole blood mode isselected (Step S7), a specimen for measurement of the number of redblood cells (RBC) and a specimen for measurement of the number of whiteblood cells (WBC) are prepared from the whole blood sample (Steps S8,S9).

With the use of the WBC measurement specimen prepared in Step S9,measurement of the WBC and the amount of hemoglobin (HGB) is performed(Step S10), and then the measured WBC and HGB are displayed on theliquid crystal display 3 a (Step S81). Subsequently, measurement of theRBC is performed with the use of the RBC measurement specimen preparedin Step S8, and the number of platelets (PLT), a hematocrit value (HCT)and other analysis items are calculated. Then, the measured RBC and thecalculated values for the respective analysis items are displayed on theliquid crystal display (Steps S13, S14).

The WBC, the RBC and the PLT are determined by counting pulsesindicative of changes in impedance between the electrodes 58 and 67 ofthe detector 50. The HGB is determined by comparing the absorbance(blank level) of the diluent alone and the absorbance of the WBCmeasurement specimen measured by the photodiode 68. The HCT isdetermined on the basis of a maximum level of the pulses indicative ofthe changes in impedance between the electrodes 58 and 67, a meancorpuscular volume (MCV), a mean corpuscular hemoglobin (MCH) and a meancorpuscular hemoglobin concentration (MCHC) are calculated from thefollowing expressions:

MCV=(HCT)/(RBC)

MCH=(HGB)/(RBC)

MCHC=(HGB)/(HCT)

Then, a fluid circuit cleaning operation is performed. Upon completionof the cleaning operation (Step S15), the diluent and the hemolyzingagent are transported from the containers 101 and 103 to the chambersSC1 and SC2, respectively on standby for the analysis of the next sample(Steps S18, S19), the routine returns to Step S3, and “Ready” isdisplayed on the liquid crystal display 3 a on standby for the analysisof the next sample. Where the pre-diluted mode is selected in Step S7,the RBC measurement specimen and the WBC measurement specimen areprepared from a pre-diluted blood sample (Steps S16, S17). In this case,the pre-diluted sample is obtained by preliminarily diluting a wholeblood sample. Therefore, a preliminary dilution factor should be takeninto account so that the RBC measurement specimen and the WBCmeasurement specimen have the same dilution factors as those preparedfrom the whole blood sample in the whole blood mode.

Next, operations to be performed in FIG. 44 (Steps) will be described indetail with reference to the flow system diagram shown in FIG. 42. Theanalyzer is of a normally-closed valve type in which all the valves inthe fluid circuit are usually closed.

Diluent Transporting Operation (Steps S1 a, S2 a, S18)

As shown in the flow chart of FIG. 45, when the valve SV13 is opened(Step S21), a negative pressure is applied to the waste liquid chamberWC from the negative pressure pump P1. Whereby, the diluent is suppliedinto the diluent chamber SC1 from the diluent container 101 through theair bubble sensor BS1. Where the air bubble sensor BS1 does not detectmore than a predetermined amount of air bubbles in a flow path (StepS22), the valve S13 is closed after the lapse of a predetermined timeperiod (Steps S23, S24). Thus, a predetermined amount of the diluent isstored in the diluent chamber SC1.

On the other hand, where the air bubble sensor BS1 detects more than thepredetermined amount of the air bubbles in the flow path in Steps S22,the control section 500 judges that no diluent is present in the diluentcontainer 101. The valve 13 is thereafter closed, and the displaysection 3 displays the judgment on the display 3 a (Steps S25, S26).

The user replenishes the diluent container 101 with the diluent orreplaces the diluent container 101 with a new one (Step S27), andpresses a “diluent replenishing completion” button on the touch panel 3b of the display section 3 (Step S28). Whereby, the routine returns toStep S21.

Hemolyzing Agent Transporting Operation (Steps S2 b, S19)

As shown in the flow chart of FIG. 46, when the valve SV9 is opened(Step S31), a negative pressure is applied to the waste liquid chamberWC from the negative pressure pump P1, whereby the hemolyzing agent issupplied into the hemolyzing chamber SC2 from the hemolyzing container103 through the air bubble sensor BS2. Where the air bubble sensor BS2does not detect more than a predetermined amount of air bubbles in aflow path (Step S32), the valve SV9 is closed after the lapse of apredetermined time period (Steps S33, S34). Thus, a predetermined amountof the hemolyzing agent is stored in the hemolyzing agent chamber SC2.

On the other hand, where the air bubble BS2 detects more than thepredetermined amount of the air bubbles in the flow path in Step S32,the control section 500 judges that no hemolyzing agent is present inthe hemolyzing agent container 103. The valve SV9 is thereafter closed,and the display section 3 displays the judgment the hemolyzing agent onthe display 3 a (Steps S35, S36).

The user replenishes the hemolyzing agent container 103 with thehemolyzing agent or replaces the hemolyzing agent container 103 with anew one (Step S37), and presses a “hemolyzing agent replenishingcompletion” button on the touch panel 3 b of the display section 3 (StepS38). Whereby, the routine returns to Step S31. Incidentally, thediluent transporting operation (Steps S1 a, S2 a, S18) and thehemolyzing agent transporting operation (Steps S2 b, S19) are notsimultaneously performed. That is, either of the operations isperformed.

Preliminary Cleaning Operation (Step S2)

(1) The pipette PT is moved to the upper side of the sample rack 18, andthen lowered as shown in FIG. 22. (At this time, the sample vessel SP1is not set in the sample setting section 6.) Then, the valve SV19 isopened to suck the diluent from the diluent chamber SC1 into the syringepump SR2, and the valve SV19 is closed.

(2) The valves SV4, SV11, SV20 are opened, and the diluent is suppliedinto the cleaner S from the syringe pump SR2 and then drained into thewaste liquid chamber WC. At the same time, the pipette PT is lifted, andthe cleaning of the exterior of the pipette PT is performed. When thetip of the pipette PT is inserted into the main body 80 of the cleanerS, the pipette PT is stopped. Thus, the cleaning of the exterior of thepipette PT is completed.

(3) With the valves SV4, SV11, SV20 kept open, the pipette PT is held atthe position shown in FIG. 32. Then, the valves SV7 is opened, and thediluent is supplied into the pipette PT from the syringe pump SR2through the syringe pump SR1. At the same time, the diluent dischargedfrom the suction port 32 of the pipette PT is drained into the wasteliquid chamber WC for cleaning the interior of the pipette PT.

(4) When the valves SV7 is closed, the flow of the diluent from thesuction port 32 of the pipette PT to the first opening 85 a is stopped,whereby the interior cleaning is completed. At this time, the suctionflow path 31 and the suction port 32 are filled with the diluent. On theother hand, the flow of the diluent from the second opening 85 b to thefirst opening 85 a is continued and, when the valves SV4, SV11, SV20 areclosed, the flow is stopped. Therefore, the suction port 32 of thepipette PT is kept filled with the diluent.

Preparation of RBC Measurement Specimen (Step S8)

(1) A negative pressure is applied to the waste liquid chamber WC fromthe negative pressure pump P1, and the valves SV14, SV10 are opened,whereby residual liquid is expelled from the detector 50 and the mixingchamber 70. Thereafter, the valves SV14, SV10 are closed.

(2) The valve SV19 is opened, and the syringe pump SR2 is operated forsuction, whereby the diluent is sucked into the syringe pump SR2 fromthe diluent chamber SC1. Then, the valve SV19 is closed.

(3) The pipette PT is lowered to be inserted into the sample vessel SP1(FIG. 22). Then, the syringe pump SR1 is operated for suction, wherebythe pipette PT sucks a predetermined amount (10 μL) of the blood sample.

(4) Then, the pipette PT is lifted. During the lifting, the valves SV4,SV20, SV11 are opened, whereby the diluent is supplied into the cleanerS from the syringe pump SR1 and drained into the waste liquid chamber WCfor cleaning the exterior of the pipette PT. Then, the valves SV4, SV20,SV11 are closed.

(5) The valves SV16, SV20 are opened, and the syringe pump SR2 isoperated for discharge, whereby a predetermined amount (1.3 mL) of thediluent is supplied into the mixing chamber 70. Then, the valves SV16,SV20 are closed.

(6) The pipette PT is moved to a position just above the mixing chamber70 and lowered. Then, the syringe pump SR1 is operated for discharge,whereby the 10-μL blood sample preliminarily sucked into the pipette PTis discharged into the mixing chamber 70. Thus, the blood sample isdiluted 130 times in the mixing chamber 70 through first-stage dilution,so that a 1.3-mL diluted sample is prepared in the mixing chamber 70.

(7) While the exterior of the pipette PT is cleaned as described above,the pipette PT is lifted. When the tip of the pipette PT is insertedinto the main body 80 of the cleaner S, the valves SV7, SV20, SV11 areopened. Thereafter, the diluent is supplied into the pipette PT from thesyringe pump SR2 through the syringe pump SR1 and drained into the wasteliquid chamber WC from the tip of the pipette PT for cleaning theinterior (inner surface) of the pipette PT. Then, the valves SV11, SV7,SV20 are closed.

(8) The valve SV6 is opened, and the air pump P3 is driven to supply airinto the mixing chamber 70, whereby the diluted sample is agitated inthe mixing chamber 70 by air bubbles. Then, the air pump P3 is stoppedand the valve SV6 is closed.

(9) The pipette PT is lowered again into the mixing chamber 70. Then,the valves SV7, SV20 are opened, and the syringe pump SR2 is operatedfor suction, whereby a predetermined amount (0.59 mL) of the first-stagediluted sample is sucked into the pipette PT. Then, the valves SV7, SV20are closed. Here, the diluent supplied from the syringe pump SR2 intothe pipette PT passes through the syringe pump SR1. When the syringepump SR2 is operated for suction and discharge of the diluent in thepipette PT, the diluent passes through the syringe pump SR1. The samestep is performed for all procedures described below.

(10) While the exterior of the pipette PT is cleaned as in Step (2) ofthe preliminary cleaning operation, the pipette PT is lifted.

(11) The valve SV14 is opened. Then, a negative pressure is applied tothe waste liquid chamber WC from the negative pressure pump P1, wherebythe residual sample in the mixing chamber 70 is drained into the wasteliquid chamber WC. Then, the valve SV14 is closed.

(12) The valves SV16, SV20 are opened, and the syringe pump SR2 isoperated for discharge, whereby the diluent is supplied into the mixingchamber 70 from the syringe pump SR2. Thereafter, the valves SV16, SV20are closed. Then, the above Step (11) is performed again. Thus, themixing chamber 70 is cleaned.

(13) The valves SV16, SV20 are opened, and the syringe pump SR2 isoperated for discharge, whereby a predetermined amount of the diluent ispreliminarily dispensed in the mixing chamber 70 from the syringe pumpSR2. Then, the valves SV16, SV20 are closed.

(14) The pipette PT is lowered. Then, the valves SV7, SV20 are opened,and the syringe pump SR2 is operated for discharge, whereby 0.2 mL outof the 0.59-mL first-stage diluted sample retained in the pipette PT isdischarged into the mixing chamber 70. Then, the valves SV7, SV20 areclosed. Thereafter, the pipette PT is lifted. During the lifting, theexterior of the pipette PT is cleaned in the aforesaid manner.

(15) The valves SV16, SV20 are opened, and the syringe pump SR2 isoperated for discharge, whereby the diluent is supplied into the mixingchamber 70 from the syringe pump SR2 for diluting the sample 750 timesfor second-stage dilution. Thus, a second-stage diluted sample isprepared. Then, the valves SV16, SV20 are closed. At this time, thesecond-stage diluted sample is agitated by air bubbles in the aforesaidmanner.

Thus, the RBC measurement specimen is prepared in the mixing chamber 70.

Preparation of WBC Measurement Specimen (Step S9)

(1) The valve SV19 is opened, the diluent is sucked into the syringepump SR2 from the diluent chamber SC1, and the valve SV19 is closed.Then, the valves SV20, SV27, SV28 are opened to cause the syringe pumpSR2 to suck 0.02-mL air. Thereafter, the valves SV20 SV27, SV28 areclosed. Flow paths are preliminary filled with the diluent.

The valves SV20, SV26, SV27 are opened, and the syringe pump SR2 isoperated for suction, whereby the hemolyzing agent is sucked into acharging line CL1 from the hemolyzing agent chamber SC2 and retained inthe charging line CL1. At this time, the suction amount of the syringepump S12 is determined so that the amount of the hemolyzing agentretained in the flow paths including the charging line CL1 becomes 0.5mL. Then, the valve SV26 is closed.

The valve SV25 is opened, and the syringe pump SR2 is operated fordischarge, whereby 1.02 mL of fluid including 0.5 mL of the diluent, 0.5mL of the hemolyzing agent and 0.02 mL of the air is discharged into thedetector 50 via a nozzle 61. Then, the valves SV20, SV25, SV27 areclosed.

(2) The pipette PT is moved to the upper side of the detector 50, andlowered. Then, the valves SV7, SV20 are opened, and the syringe pump SR2is operated for discharge, whereby 0.39 mL of the first-stage dilutedsample is discharged into the detector 50 from the pipette PT. Then, thevalves SV7, SV20 are closed.

Thus, 0.5 mL of the diluent, 0.39 mL of the first-stage diluted sampleand 0.5 mL of the hemolyzing agent are present in the first and thirdcontainers 51, 53 of the detector 50.

(3) The pipette PT is lifted, and the exterior and interior of thepipette PT are cleaned in the aforesaid manner.

(4) The valve SV5 is opened, and the air pump P3 is operated to supplyair into the detector 50 for agitation with air bubbles. Then, the airpump P3 is stopped, and the valve SV5 is closed. Thus, the preparationof the WBC measurement specimen in the first and third containers 51, 53of the detector 50 is completed.

Measurement of WBC and HGB (Step S10)

(1) The valves SV18, SV23 are opened. Then, a negative pressure isapplied to the waste liquid chamber WC from the negative pressure pumpP1, whereby the diluent is caused to flow from the diluent chamber SC1to the waste liquid chamber WC through the second container chamber 52of the detector 50. Thus, the second container chamber 52 is cleaned,and the diluent is retained in the second container chamber 52. Then,the valves SV18, SV23 are closed.

(2) The valve SV24 is opened, and the syringe pump SR2 is operated forsuction, whereby the WBC measurement specimen is caused to flow from thefirst and third container chambers 51, 53 into the second containerchamber 52 via the orifice 55 in the detector 50 (for about 10 seconds).Then, the valve SV24 is closed. At this time, the resistance-typedetecting section 503 detects changes in impedance between theelectrodes 58 and 67, and the control section 500 calculates the numberof the white blood cells (WBC) on the basis of the detection result.

(3) At the same time, light emitted from the light emitting diode 68 istransmitted through the specimen, and the intensity of the transmittedlight of the third container chamber 53 is detected by the photodiode69. The control section 500 calculates the amount of the hemoglobin(HGB) on the basis of the detected light intensity. The blankmeasurement of the HUB (measurement of the intensity of lighttransmitted through the diluent) is performed immediately after Step (1)of the WBC measurement specimen preparing operation.

Measurement of RBC (Step S12)

(1) The valve SV10 is opened, and a negative pressure is applied to thewaste liquid chamber WC from the negative pressure pump P1, wherebyresidual liquid in the detector 50 is drained into the waste liquidchamber WC. Then, the valve SV10 is closed.

(2) The valves SV15, SV20 are opened, and the syringe pump SR2 isoperated for discharge, whereby the diluent is supplied into the firstand third container chambers 51, 53 via the nozzle 60 of the detector50. Then, the valves SV15, SV20 are closed.

(3) The valves SV18, SV23 are opened, and a negative pressure is appliedto the waste liquid chamber WC from the negative pressure pump P1,whereby the diluent is supplied from the diluent chamber SC1 into thesecond container chamber 52 of the detector 50 for cleaning the secondcontainer chamber 52. Then, the valves SV18, SV23 are closed.

(4) The valves SV1, SV12, SV20 are opened, and the syringe pump 52 isoperated for suction, whereby the RBC measurement specimen is suckedfrom the mixing chamber 70 into a charging line CL2 and retained in thecharging line CL2. Then, the valves SV1, SV12, SV20 are closed.

(5) The valve SV24 is opened, and the syringe pump S12 is operated fordischarge, whereby the diluent flows from the third container chamber 52into the first container chamber 51 through the orifice 55 in thedetector 50.

(6) During this period, the syringe pump SR4 is operated for discharge,whereby the RBC measurement specimen retained in the charging line CL2is ejected from the jet nozzle 56 toward the orifice 55. The RBCmeasurement specimen ejected from the jet nozzle 56 is surrounded by thediluent in the preceding Step (5), and passes as a sheath flow throughthe orifice 55 (for about 10 seconds). Then, the valve SV24 is closed.

(7) The control section 500 calculates the number of the red blood cells(RBC), the number of the platelets (PLT), the hematocrit (HCT) and otheranalysis items on the basis of changes in impedance between theelectrodes 58 and 67 when the sheath flow passes through the orifice 55.

Cleaning Operation (Step S15)

(1) The valves SV10, SV14 are opened, and then a negative pressure isapplied to the waste liquid chamber WC from the negative pressure pumpP1, whereby residual liquid in the mixing chamber 70 and the detector 50is drained into the waste liquid chamber WC. Then, the valves SV10, SV14are closed.

(2) The valves SV15, SV16, SV20 are opened, and the syringe pump SR2 isoperated for discharge, whereby the diluent is supplied into the mixingchamber 70 and the detector 50. Then, the valves SV15, SV16, SV20 areclosed.

(3) The valves SV1, SV2 are opened, and then a negative pressure isapplied to the waste liquid chamber WC from the negative pressure pumpP1, whereby the diluent is drained from the mixing chamber 70 into thewaste liquid chamber WC through the charging line CL2. Then, the valvesSV1, SV2 are closed.

Thus, the cleaning operation is completed. The negative pressure in thewaste liquid chamber WC is monitored by the pressure sensor J6, and thenegative pressure pump P1 is driven to constantly keep the pressurewithin a range between 100 and 300 mmHg, preferably between 150 and 200mmHg.

When the amount of the waste liquid stored in the waste liquid chamberWC reaches a predetermined amount, this situation is detected by thefloat switch J7, and the liquid draining pump P2 is driven by the floatswitch J7, whereby the waste liquid is drained into the waste liquidcontainer 102.

Characteristics of Liquid Transfer

FIG. 47 is a detailed diagram of a major portion of the fluid circuitshown in FIG. 42.

As shown, the fluid circuit includes a tube-shaped third retainingportion (charging line) CL1 with a first opening M1 and a second openingM2 provided at both ends thereof, a liquid discharge portion (nozzle)61, a single syringe pimp SR2 having a first suction port N1 and asecond suction and discharge port N2, a first retaining portion (diluentchamber) SC1 for storing a first liquid (diluent), and a secondretaining portion (hemolyzing agent chamber) SC2 for storing a secondliquid (hemolyzing agent).

Opening/closing valves SV19, SV27, SV26 and SV25 are respectivelyprovided between the first retaining SC1 and the first suction port N1,between the first opening M1 and the second suction and discharge portN2, between the second retaining portion SC2 and the second opening M2,and between the second opening M2 and the liquid discharge section 61,which are connected via flow paths.

Further, an opening/closing valve SV28 for communicating with theatmosphere is connected to the second opening M2 through the flow paths.The flow paths are preliminarily filled with the first liquid (i.e., thediluent).

In this arrangement, the following steps are performed:

(1) The valve SV19 is first opened, and the diluent is sucked into thesyringe pump SR2 from the diluent chamber SC1. Then, the valve SV19 isclosed.

(2) Next, the valves SV28, SV27 are opened, and the syringe pump SR2 isoperated for suction, whereby a predetermined volume (20 μL) of air issucked into the flow path to provide an air layer in the third retainingportion (the charging line) CL1. Thereafter, the valve SV28 is closed.

(3) The valve SV26 is opened, and the syringe pump SR2 is operated forsuction. Whereby, a predetermined amount (0.5 mL) of the hemolyzingagent is sucked from the hemolyzing agent chamber SC2 into the flow pathbetween the point S and the second opening M2 and the charging line CL1.Then, the valve SV26 is closed.

(4) The valve SV25 is opened, and the syringe pump SR1 is operated fordischarge, whereby 0.5 in L of the diluent, 0.5 mL of the hemolyzingagent and 0.02 mL of the air are discharged into the detector 50 via thenozzle 61. Then, all the valves are closed.

With this arrangement, two kinds of liquids such as the diluent and thehemolyzing agent can be quantitatively dispensed by the single syringepump 52.

The air layer provided in the flow paths prevents the diluent betweenthe syringe pump SR2 and the charging line CL1 from being mixed with thehemolyzing agent.

In this embodiment, the liquid is discharged into the upper-opendetector 50 via the nozzle 61, but may be discharged into a closeddetector or chamber via a nipple (liquid discharge portion).

Construction of Syringe Pump Unit

FIG. 48 is a front view of a syringe pump unit PU shown in FIG. 42.

As shown, the syringe pumps SR1, SR4 to be paired are fixed in line to asupport plate 601 so as to be opposed to each other. A sliding rail 602is provided on the support plate 601 parallel to the syringe pumps SR1,SR4, and a driving pulley 603 and a driven pulley 604 are rotatablyprovided on upper and lower portions of the support plate 601,respectively.

A syringe pump motor STM4 provided on the rear side of the support plate603 causes the driving pulley 603 to be rotatably driven. A timing belt605 is stretched between the pulleys 603 and 604. The sliding rail 602supports a sliding member 606 in a slidable manner. The sliding member606 is coupled with the timing belt 605 via a coupling member 607thereby to be moved vertically up and down by the syringe pump motorSTM4.

Pistons 608, 608 a of the syringe pumps SR1, SR2 respectively haveterminals 609, 609 a provided at their distal ends. The terminals 609,609 a are connected to each other by means of the engaging member 600,and the engaging member 600 is connected to the sliding member 606. Whenthe syringe pump motor STM4 is driven, the pistons 608, 608 a cooperateto move vertically up and down.

FIG. 49 is a vertical sectional view of a syringe pump SR1. The syringepump SR2 has substantially the same construction as the syringe pumpSR1. As shown, the piston 608 extends from a lower end portion of acylinder 610 with a cylindrical hollow portion 611 provided therein, andcan vertically be inserted into the hollow portion 611. A suction anddischarge nipple 612 is provided at an upper end of the cylinder 610 forcommunicating with the hollow portion 611, and another suction anddischarge nipple 613 is provided in the vicinity of a lower end of thecylinder 610 for communicating with the hollow portion 611.

O-rings 614, 615, a seal 616 and a collar 617 employed for sealing a gapbetween the piston 608 and the hollow portion 611 are fixed to a lowerend portion of the cylinder 610 by a cap 618 with inside screws. Acleaning member (sponge) 619 for cleaning an outer surface of the piston608 is fixed to the cap 618 by means of a cap 620.

In the syringe pump SR1, a liquid is sucked through the nipples 612 and613 into the hollow portion 611 after the lowering of the piston 608,and the sucked liquid is discharged through the nipples 612 and 613after the lifting of the piston 608. On the contrary, the syringe pumpSR4 is operated for discharge and suction in a reversed manner.

Each of the syringe pumps SR1 and SR2 serves as one flow path becausethe nipples 612 respectively communicate with the nipples 613 throughthe hollow portions 611. The syringe pump SR1 is fastened to a fixingportion 622 by a nut 623. The fixing portion 622 is preliminarily fixedto the support plate 601 by a screw 621.

FIGS. 50 to 52 are diagrams for explaining an engaging relationshipbetween the terminals 609, 609 a of the syringe pumps SR1, SR2 and theengaging member 600.

As shown in FIG. 50, the terminal 609 fixed to the distal end of thepiston 608 includes a pair of flanges 624, 625, and the terminal 609 afixed to the distal end of the piston 608 a includes a pair of flanges624 a, 625 a. The flanges 624, 625 are provided at an interval W1, andthe flanges 624 a, 625 a are also provided at an interval W1.

The engaging member 600 has fingers 626, 627 with their widths W2, W3,respectively. The fingers 626, 627 are respectively inserted between theflanges 624, 625 and between the flanges 624 a, 625 a.

W1, W2 and W3 have a relationship of W1>W2>W3, for example, W1=2.5 mm,W2=2.4 mm and W3=2.0 mm.

In this arrangement, when the engaging member 600 is moved in an arrowdirection Z1, the finger 626 is first brought into contact with theflange 625 as shown in FIG. 51 thereby to drive the piston 608 in thearrow direction Z1, and then the finger 627 is brought into contact withthe flange 624 a as shown in FIG. 52 thereby to drive the piston 608 ain the arrow direction Z1. Accordingly, the engaging member 600 isdriven in the arrow direction Z1 in association with the movement of thepistons 608, 608 a.

In the state shown in FIG. 52, when the engaging member 600 is moved inan arrow direction Z2, the finger 626 is first brought into contact withthe flange 624 thereby to drive the piston 608 in the arrow directionZ2, and then the finger 627 is brought into contact with the flange 625a thereby to drive the piston 608 a in the arrow direction Z2.Accordingly, the engaging member 600 is driven in the arrow direction Z2in association with the movement of the pistons 608, 608 a.

Thus, the engaging member 600 and the terminals 609, 609 a transmit adriving force supplied from the syringe pump motor STM4 to the pistons608, 608 a with a time lag between the pistons, and then the pistons608, 608 a start driving vertically.

Therefore, the syringe pump motor STM4 is prevented from being heavilyloaded simultaneously by static friction between the pistons 608, 608 aand the cylinders, so that the syringe pump motor STM4 can be operatedat a reduced capacity. The terminals 609, 609 a are not necessarilyrequired to be fixed to the distal ends of the pistons 608, 608 a,respectively, but may be fixed at some midpoints of the pistons 608, 608a.

Further, the pistons 608, 608 a are not necessarily required to beprovided in line, but may be provided parallel to each other so that theaxis of the piston 608 is offset from that of the piston 608 a.

Still further, the fingers 626 and 627 of the engaging member 600 may berespectively set to have the same widths W2 and W3, and the interval W1between the flanges 624 and 625 may be smaller than that between theflanges 624 a and 625 a.

Constructions of Air Bubble Sensors BS1, BS2

FIG. 53 is a top surface view of an air bubble sensor BS1, and FIG. 54is a view from an A-A arrow direction in FIG. 53.

As shown, the air bubble sensor BS1 is comprised of a main body 650composed of a transparent resin such as a polyether imide, a flow path651 having an oblong shape in section provided in the main body 650, andnipples 652, 653 connected to both ends of the flow path 651. The mainbody 650 is integrated with a photo-interrupter 654 as shown in FIGS. 53and 54. The photo-interrupter 654 includes a light emitting element (forexample, a LED) 655 and a photo-receptive element 656 (for example, aphotodiode). An air bubble sensor BS2 has substantially the sameconstruction as the air bubble sensor BS1.

When light LT is emitted from the light emitting element 655 to theempty flow path 651, the light LT incident at an angle of 45 degrees istotally reflected at a wall of the empty flow path 651 as shown in FIG.54. Accordingly, the light LT does not reach the photo-receptive element656. On the other hand, when light LT is emitted from the light emittingelement 655 to the flow path 651 filled with a liquid, the light LTpasses through the wall of the flow path 651 to reach thephoto-receptive element 656 because of the refraction of the light LTwith respect to the liquid.

An output from the photo-receptive element 656 is converted to a logicsignal (binary signal) of “1” or “2” by a conversion circuit (not shown)provided in the photo-interrupter 654, and outputted as a detectionsignal of the air bubble sensor BS1. That is, when the liquid flows fromthe nipple 652 into the nipple 653 through the flow path 651, the airbubble sensor BS1 outputs the signal “0” while the flow path 651 isfilled with the liquid, and outputs the signal “1” while thephoto-receptive element 656 cannot receive the light LT due to thepresence of air bubbles in the flow path 651. The air bubble sensor BS2operates in the same manner as in the air bubble BS1. For example,GP1A05E commercially available from Sharp Kabushiki Kaisha can be usedfor the photo-interrupter 654.

FIG. 55 is a circuit diagram illustrating a signal processing circuit inwhich the control section 500 (FIG. 43) judges whether air bubbles aregenerated by receiving respectively outputs V1, V2 from the air bubblesensors BS1, BS2.

The drive circuit section 501 (FIG. 43) includes an OR gate 504 and apulse width integrating circuit 505 for integrating periods (pulsewidths) during which the signal “1” is outputted from the OR gate 504. Alogical sum Vp of the outputs V, V2 binary signals) from the air bubblesensors BS1, BS2 is calculated to be outputted to the pulse widthintegrating circuit 505. As described above, the control section 500including the CPU controls the drive circuit section 501, and allowsvalves SV13, SV9 to be driven.

FIGS. 56 and 57 are timing charts illustrating respectively arelationship between a driving voltage DV13 of the valve SV13 and theoutput Vp from the OR gate 504, and a relationship between a drivingvoltage DV9 of the valve SV9 and the output Vp from the OR gate 504.

As shown in FIG. 56, the driving voltage DV13 is turned on, and thevalve SV13 is driven, whereby the diluent is transported from thediluent container 101 (FIG. 42) into the diluent chamber SC1 (FIG. 42).At this time, where the air bubble sensor BS1 detects air bubbles, theoutput V1 from the air bubble sensor BS1 is represented as a pulsesignal.

On the other hand, the air bubble sensor BS2 is filled with thehemolyzing agent, so that the output V2 remains the signal “0”. Sincethe output Vp from the OR gate is the logical sum of the outputs V1, V2,the output Vp is represented as a pulse signal shown in FIG. 56.

The pulse width integrating circuit 505 integrates periods T duringwhich the output Vp is changed to the signal “1” within a predeterminedtime period, and the periods T thus integrated are outputted to thecontrol section 500. The control section 500 judges whether to generatethe air bubbles on the basis of an integrated value, and then comparesthe integrated value with a predetermined value. At this time, where theintegrated value is larger than the predetermined value, the controlsection 500 judges that the diluent is not transported to the diluentchamber SC1. That is, the diluent container 101 is determined empty bythe control section 500. Thereafter, the control section 500 causes thedisplay section 3 to display the judgment on the display 3 a. That is,the control section 500 judges that no diluent is present in the diluentcontainer 101 when the driving voltage DV13 of the valve SV13 is turnedon and the integrated value obtained within the predetermined timeperiod is larger than the predetermined value.

As shown in FIG. 57, the driving voltage DV9 is turned on, and the valveSV9 is driven, whereby the hemolyzing agent is transported from thehemolyzing agent container 103 (FIG. 42) into the hemolyzing chamber SC2(FIG. 42). At this time, where the air bubble sensor BS2 detects airbubbles, the output V2 from the air bubble sensor BS2 is represented asa pulse signal.

On the other hand, the air bubble sensor BS1 is filled with the diluent,so that the output V1 remains the signal “0”. Since the output Vp fromthe OR gate 504 is the logical sum of the outputs V1, V2, the output Vpis represented as a pulse signal shown in FIG. 57.

The pulse width integrating circuit 505 integrates periods T duringwhich the output Vp is changed to the signal “1” within thepredetermined time period, and the periods T thus integrated areoutputted to the control section 500. The control section 500 judgeswhether to generate the air bubbles on the basis of an integrated value,and then compares the integrated value with the predetermined value. Atthis time, where the integrated value is larger than the predeterminedvalue, the control section 500 judges that the hemolyzing agent is nottransported to the hemolyzing agent chamber SC2. That is, the hemolyzingagent container 103 is determined empty by the control section 500.Thereafter, the control section 500 causes the display section 3 todisplay the judgment on the display 3 a. That is, the control section500 judges that no hemolyzing agent is present in the hemolyzing agentcontainer 103 when the driving voltage DV9 of the valve SV9 is turned onand the integrated value obtained within the predetermined time periodis larger than the predetermined value.

FIG. 58 is a circuit diagram illustrating another exemplary signalprocessing circuit in which the control section 500 (FIG. 43) judgeswhether air bubbles are generated by receiving respectively the outputsV1, V2 from the air bubble sensors BS1, BS2. In this circuit, aswitching circuit 506 is used instead of the OR gate of the signalprocessing circuit shown in FIG. 55.

FIG. 59 is a timing chart illustrating a relationship among the drivingvoltages DV13, DV9 of the respective valves SV13, SV9, the output Vpfrom the OR gate 504 and the switching operation of the switchingcircuit 506.

As shown in FIG. 59, the driving voltage DV13 is turned on, and a switchof the switching circuit 506 is switched to SW1, whereby the output Vpinputted to the pulse width integrating circuit 505 becomes equal to theoutput V1. The pulse width integrating circuit 505 integrates periods Tduring which the output Vp is changed to the signal “1” within thepredetermined time period, and the periods T thus integrated areoutputted to the control section 500. The control section 500 judgeswhether to generate the air bubbles on the basis of an integrated value,and then compares the integrated value with the predetermined value. Atthis time, where the integrated value is larger than the predeterminedvalue, the control section 500 judges that the diluent is nottransported to the diluent chamber SC1. Thereafter, the control section500 causes the display section 3 to display the judgment on the display3 a. That is, the control section 500 judges that no diluent is presentin the diluent container 101 when the driving voltage DV13 of the valveSV13 is turned on and the integrated value obtained within thepredetermined time period is larger than the predetermined value.

As shown in FIG. 59, the driving voltage DV9 is turned on, and theswitch of the switching circuit 506 is switched to SW2, whereby theoutput Vp inputted to the pulse width integrating circuit 505 becomesequal to the output V2. The pulse width integrating circuit 505integrates the periods T during which the output Vp is changed to thesignal “1” within the predetermined time period, and the periods T thusintegrated are outputted to the control section 500. The control section500 judges whether to generate the air bubbles on the basis of theintegrated value, and then compares the integrated value with thepredetermined value. At this time, where the integrated value is largerthan the predetermined value, the control section 500 judges that thehemolyzing agent is not transported to the hemolyzing agent chamber SC2.Thereafter, the control section 500 causes the display section 3 todisplay the judgment on the display 3 a. That is, the control section500 judges that no hemolyzing agent is present in the hemolyzingcontainer 103 when the driving voltage DV9 of the valve SV9 is turned onand the integrated value obtained within the predetermined time periodis larger than the predetermined value.

FIG. 60 is an exemplary of another switching circuit which can be usedinstead of the switching circuit 506 of FIG. 58. A switching circuit 507comprises two AND gates 507 a, 507 b and an OR gate 507 c.

Where an output from the CPU is the signal “1”, the signal “1” isinputted to the AND gate 507 a and the signal “0” is inputted to the ANDgate 507 b. Therefore, an output V3 from the AND gate 507 a is changedto the signal “1” only when the output V1 is the signal “1”. On theother hand, an output V4 from the AND gate 507 b is changed to thesignal “0” irrespective of the signal of the output V2 from the airbubble sensor BS2. That is, the output Vp becomes equal to the output V1when the output from the CPU is the signal “1”.

Where the output from the CPU is the signal “0”, the signal “0” isinputted to the AND gate 507 a and the signal “1” in inputted to the ANDgate 507 b. Therefore, the output V3 from the AND gate 507 a is changedto the signal “0” irrespective of the signal of output V1 from the airbubble sensor BS1. On the other hand, the output V4 from the AND gate507 b is changed to the signal “1” only when the output V2 from the airbubble sensor BS2 is the signal “1”. That is, the output Vp becomesequal to the output V2 when the output from the CPU is the signal “0”.

According to this invention, the liquid aspirator has the plurality ofelongated recesses formed in the outer surface of the hollow pipethereof. When the liquid aspirator is stuck into the sample vessel withthe rubber cap, the inside of the sample vessel immediately communicateswith the atmosphere through each of the recesses. Therefore, the samplecan smoothly be sucked and quantified through the liquid aspirator, sothat analysis accuracy can be improved. At least one of the recesses canbe prevented from being filled with the rubber cap when the liquidaspirator virtually reaches the bottom of the sample vessel. Inaddition, when the exterior of the liquid aspirator is cleaned, therecesses are cleaned at the same time, and therefore the analyzer doesnot need to further provide a cleaning flow system for cleaning therecesses.

1. A sample analyzer, comprising: a preparing section for preparing an analysis sample to be analyzed using a sample, a first liquid and a second liquid; and a detector for detecting a signal from the analysis sample, wherein the preparing section comprises a liquid transfer unit, the liquid transfer unit including: a pump connected to a first liquid retaining section for storing the first liquid and a second liquid retaining section for storing the second liquid; a flow path for connecting between the pump and the second liquid retaining section; a third liquid retaining section placed in the flow path; and a liquid discharge section connected to the third liquid retaining section; the pump transporting the second liquid from the second liquid retaining section to the third liquid retaining section and discharging the second liquid with the first liquid via the liquid discharge section to the detector.
 2. The sample analyzer of claim 1, wherein the third liquid retaining section is tubular.
 3. The sample analyzer of claim 1, wherein the flow path comprises: a first flow path provided between the second and third liquid retaining sections; and a second flow path provided between the third liquid retaining section and the pump, and wherein the liquid transfer unit further comprises: a third flow path provided between the pump and the first liquid retaining section; a forth flow path provided between the third liquid retaining section and the liquid discharge section; and first, second, third and forth valves for opening and closing the first, second, third and forth flow paths, respectively.
 4. The sample analyzer of claim 1, wherein the liquid transfer unit comprises an air flow path for supplying air to the third liquid retaining section, the pump supplying the air to the third liquid retaining section through the air flow path before transporting the second liquid to the third liquid retaining section.
 5. The sample analyzer of claim 1, wherein the first liquid is a diluent and the second liquid is a hemolyzing agent.
 6. The sample analyzer of claim 1, further comprising: a first valve for connecting and isolating the first liquid retaining section and the pump; and a second valve for connecting and isolating the second liquid retaining section and the pump, wherein the first valve is opened and the second valve is closed when the pump sucks the first liquid, and the second valve is opened and the first valve is closed when the pump sucks the second liquid.
 7. A sample analyzer, comprising: a chamber for preparing an analysis sample by mixing a sample, a first liquid and a second liquid; a detector for detecting a signal from the analysis sample supplied by the chamber; a pipette for supplying the sample to the chamber; a liquid transfer unit for supplying the first liquid and the second liquid to the chamber; and a controller for controlling the liquid transfer unit, wherein the liquid transfer unit comprises, a pump controlled by the controller, a first liquid retainer for storing the first liquid, a first flow path connected between the pump and the first liquid retainer, a second liquid retainer for storing the second liquid, a third liquid retainer, a second flow path connected between the pump and the third liquid retainer, a liquid discharge port for discharging the first and second liquids to the chamber, and a third flow path connected to the second liquid retainer, the third liquid retainer, and the liquid discharge port.
 8. The sample analyzer of claim 7, wherein the third liquid retainer is tubular.
 9. The sample analyzer of claim 7, wherein the third flow path comprises an air flow path for supplying air to the third liquid retainer.
 10. The sample analyzer of claim 7, wherein the first flow path comprises a first valve for opening and closing the first flow path, the second flow path comprises a second valve for opening and closing the second flow path, and the third flow path comprises a third valve for opening and closing a flow path between the second liquid retainer and the third liquid retainer, and a fourth valve for opening and losing a flow path between the third liquid retainer and the liquid discharge port, wherein the first to fourth valves are controlled by the controller.
 11. The sample analyzer of claim 9, wherein the air flow path comprises a fifth valve for opening and closing the air flow path, the fifth valve controlled by the controller.
 12. The sample analyzer of claim 7, wherein the first liquid is a diluent and the second liquid is a hemolyzing agent.
 13. The sample analyzer of claim 10, wherein the controller controls the pump, the first valve, and the second valve so that the first valve is opened and the second valve is closed when the pump sucks the first liquid.
 14. The sample analyzer of claim 13, wherein the controller controls the pump and the first to fourth valves so that the second and third valves are opened and the first and fourth valves are closed when the pump sucks the second liquid.
 15. The sample analyzer of claim 14, wherein the controller controls the pump and the first to fourth valve so that the second and fourth valves are opened and the first and third valves are closed when the pump discharges the first and second liquid. 